Safety control for vulcanizer presses



J 11, 1940- R. F. SANDBERG El AL 2,204,513

SAFETY CONTROL FOR VULCANIZER PRESSES Filed May 26, 1957 //v VEN T0 Rs.-RAF. SANDBER G, EEK. ERBGUTH.

E8 SMITH JR. BY 4 TTORNE VJ Patented June 11, 1940 UNITED STATES PATENTOFFICE SAFETY CONTROL FOR VULCANIZER PRESSES York Application May 26,1937, Serial No. 144,821

Claims.

This invention relates to timers for safely controlling the cycle ofoperation of individual vulcanizer presses for hollow tires. Itparticularly relates to arrangements wherein one such timer -5 controlsthe operation of two or more such presses.

A particular object of the present invention is to provide a controllingsystem with safety interlocks functioning to give a reliability of opera'10 tion and assurance of safety to the operator hitherto unobtainablein this art. While others have controlled only the exhaust from theinterior of the tires, we also positively block the entrance of eithersteam or hot water to the in- 15,1et line to the interior of the tiresand simultaneously connect the same to a drain.

As regards safety of operation, it is axiomatic that a control systemmust be safe both when automatically and when manually operated. 'We

attain this end, not by a mere aggregation of old elements andinstrumentalities, but by so modifying the arrangement and organizationof our apparatus as to provide greater safety by a new combination.

We also use a permissive running arrangement in which the timer ismanually started and runs uninterruptedly through its cycle if thepressure in the exhaust line is above a predetermined minimum at a timenear the beginning of the cycle after the presses are closed, so thatthe timer will not continue to operate unless a tire is in each press.

These and other objects of our invention will appear to those skilled inthe art from the ac-' ,u companying drawing and specification, in whichis illustrated and described a specific embodiment of our invention. Itis our intention to claim all that we have disclosed that is new anduseful.

The drawing shows the electrical, pneumatic 40 and hydraulic circuitsand their associated operative members, including a cam for a timergoverning two presses, for the preferred embodiment of our improvedsafety method utilizing the permissive starting arrangement inconnection with two push-buttons.

The description of the equipment and its operation is in the order ofthe following resume:

A. General description; and

B. Detailed description of the preferred illustrated embodiment of ourinvention.

Throughout the description, it must be remembered that there are threeconditions of operation; (1) normal, (2) manual, and (3) for week- ;5ends, or other protracted periods of plant inactivity, during which thepresses are closed and W the molds kept heated but do not contain tires.

A. General description Before proceeding with the detailed descriptionfor a typical cure, it is believed hel ful to give the following briefgeneral description to make clear the functioning of the variousoperating parts.

Fig. 1 is a diagrammatic view of the controlling v 0 system, showing thetimer in front elevation. Fig. 2 is a side elevation, partially insection, of a detail of the timer viewed from the left-hand side inFig. 1. In the figures, each individual tire mold press is hydraulicallyactuated by a piston governed by a reversing valve which is air-operatedby a spring-opposed diaphragm. After both presses are closed, steam isadmitted to the interior of each hollow tire on one side and steam issimultaneously exhausted to a drain from its other side by valves whichare likewise air-operated by spring-opposed diaphragms. After the air isblown out, the steam is shut off and hot water under pressure of severalhundred lbs. per sq. in. is circulated through the tire and 5 returnedby a 3-way exhaust valve to the circulating system instead of to adrain. The timer controls, by a single cam, the sequential operation ofthe air-valves for the several diaphragms. This cam positions a singlecontrolling member that operates these air-valves to give the desiredsequence of operations according to flue various displacements of thismember. The cam. is rotated by a self-starting synchronous motorprecisely geared to make exactly one revolution for one complete cycleof operation take the desired time.

With the timer shown, the attendant starts the timer by simultaneouslypressing two push-buttons, causing the cam to run steadily forward so 40that each press closes, after which steam is admitted to the interior ofthe tire. The running switch of the timer is so arranged that the timerwill stop unless the pressure in the exhaust has risen after apredetermined interval following the manual starting of the timer,failure to rise ordinarily being due to the absence of a tire fromeither press or failure of either of the molds to close. However, in thenormal operation of this timer, it will run continuously throughout thecycle. While this permissive feature is similar in some respects to thatshown in the Bast et a1. Patent No. 1,959,336, we have applied theteachings thereof, which are for a pot heater containing a number oftires,'in a novel manner valve, having a weaker spring to the individualmold presses which face a different problem; that of safely operatingsuch presses, a result which we attain with our improved system.

The steam cannot be introduced until after each press has been closed.If, for any reason, the timer stops, this is indicated by the runninglight on top of the timer. As long as the press is closed, steam and hotwater may be admitted to the interior of the tire, and the exhaust lineis connected either to drain or to circulate. Whenever air pressure doesnot reach the diaphragm of the hydraulic reversing valve, it is held inits press-closing position by the diaphragm-opposing spring.Consequently, failure of the air-supply cannot cause the press to open.At the end of the cure, the timer shuts off the flow of hot water,admits steam to blow out the hot water to the exhaust, and then stopsthe flow of steam, leaving the exhaust open. The timer then closes a3-way block valve in the inlet line to the tire, simultaneously openingsuch line to the atmosphere, and, after a safe interval, operates thehydraulic reversing valve; the block than the hydraulic reversing valve,will close at a lower air pressure, and the hydraulic reversing valve isadditionally provided with a capacity-tank and a checkshunted resistancein series therewith to delay the opening, but not the closing, of eachpress. Each press opens after a predetermined interval following theclosure of both steam and hot water supply valves and the opening of theexhaust valve to drain.

B. Detailed description In the drawing, a single timer l0 controls apair of individual tire vulcanizing presses each press having a movablemold l2 operable by hydraulic piston l3 in its cylinder I4. The openingand closing ends of hydraulic cylinder M are connected with hydraulicreversing valve if: by the opening and closing lines l6 and I1respectively. Hydraulic pressure supply line If! is connected to thehydraulic reversing valve as is its exhaust hydraulic line I9. Hydraulicreversing valve |5 is positioned by air-operated diaphragm 2|) opposedby a strong spring 2|. A 3-way block valve 3'! is likewise positioned byair-operated diaphragm 38 of the same size as diaphragm and opposed by aweaker spring 39, the arrangement being such that valve 31 well havemoved to completely block the fluids entering the supply line 35 andconnect the same to atmosphere before reversing valve i5 is moved at allfrom its press-closing position. Steam supply valve 22 is likewisepositioned by its air-operated diaphragm 23 opposed by spring 24, thisvalve being of the spring-closed type as is also hot water supply valve25 with its airoperated diaphragm 26 opposed by spring 21. Exhaust valve28 is air-operated by its diaphragm 2S opposed by spring 30; This valveis of the 3-way type for selectively connecting the exhaust with drain3| or circulating line 32, which is connected back to the inlet of hotwater valve 25, the exhaust line 33 from the interior of the tires beingconnected therewith at 34. Inlet line 35 is connected with the interiorof each tire at inlet connection 36, to connect steam and hot watervalves 22 and 25 through block valve 31 with the interior of the tires.

In timer l0, an electric motor of the selfstarting synchronous typedrives changeable gears 4| and 42, and shaft 43, to which disc cam 44 isattached normal to the axis of shaft 43. Cylinder hub 45 of the cam hasbraking ball 46 movable vertically in a fixed groove 4'! so that the camcan turn freely only in a forward direction, i. e., clockwise in thefigure. The periphery of cam 44 is made up of circular portions ofdifferent radii corresponding with the desired operations. Air nozzle 48has ball 49 attached thereto to act as a sled-runner and thus space theend of air nozzle 48 just clear of the front surface of the cam so thatit cannot hinder the motion thereof. Air-supply line 50 contains cock5|, normally open but shown closed by its handle 5| in the drawing.Bellows 52, connected to air-supply line 50 is fixed at its upper end,the lower end being free to expand downwardly with an increase ofair-pressure therein. Feed resistance 53 is located in the air-supplyline just upstream of the bellows. Flexible air-line 54 connects theinterior of bellows 52 with nozzle 43, which nozzle is attached to thelefthand end of lever 55, which is pivotally connected by pin 56 to theframe ll! of timer l0 and to the depending portion 51 of bellows 52 bypin 58 attached thereto so that the motion of the bellows results in acorresponding magnified motion of nozzle 48. Roller 59 is rotatablymounted on pin 60 also attached to the lower end of depending portion 51of bellows 52. Control lever 8| is pivotally mounted at its lefthand endon pin 62 which is attached to timer frame H), the righthand end beingbiased upwardly by tension spring 53, the upper end of which is likewiseattached to timer frame I to the bottom portion of bellows 52 pressesagainst the upper edge of control lever 6| to position it according tothe then effective edge of cam 44. Bumps on the lower edge of controllever 6| coactingly abut air-valves 64, 65 and 66 respectively foroperating the reversing valve l5 for the presses, steam valve 22 and hotwater valve 25. Adjustable bumper head 61, having sliding pin 68 biaseddownwardly by spring 59,

Roller 59 attached is provided for each of the air-valves so that thelower end of sliding pin 68 may abut the corre-' sponding stem 10 ofeach of air-valves S4, 65 and 68. Each air-valve is connected withairsupply line 50 downstream of cock 5|. Airvalve 66 is connected byline TI to diaphragms,

2E and 29 respectively of hot water valve 25 and exhaust valve 23,air-valve 66 being of the reverse-acting type so that line II isnormally disconnected thereby from air-supply line 50 and, when stem 10of air-valve 66 is depressed, the air-pressure reaches line H fromair-supply 50. Line 12 connects air-valve 65 with diaphragm 23 of steamvalve 22. This air-line 12 contains reverse-acting air-valves 13 whichare closed except when movable molds |2 of presses H are closed, atwhich time these air-valves "l3 connect control air-valve 65 withdiaphragm 23. Line 14 connects air-valve 64 with diaphragm 23 ofhydraulic reversing valve l5. This line is also connected with thediaphragm 38 of block valve 31, as before mentioned. Line M alsocontains capacity tank H with series-resistance 18 and check valve 19shunted around resistance 18 so that each press closes quickly andpromptly, but opens slowly and in a delayed manner.

To operate electrical motor 40 of timer l0, an electrical system isprovided as follows: blade 80 is biased downwardly by its own elasticityso that its end portion may abut stud-cam 8| on the face of cam 44.Running blade 83 is connected to one line 82 of the current supply.Blade 80 opens the same from blade 81.

from running-blade 83 when stud-cam 8| raises the end of blade 88. Blade88 is connected by wire 84 with the lower terminal 85 of coil 88 ofmotor 48. The running of motor 48 turns cam 44 so that its stud-cam 8|"raises blade 88' to close against starting blade 81, which is connectedby wire 88 containing two push-buttons 89 (giving two-hand safetystarting), with wire 84 which is connected with lower terminal 85 ofmotorcoil 88, this wire 88 also contains an additional switch means anda relay holding-coil, as will be described later. The upper terminal 98of coil 86, which is shunted through neon-light 9|, is connected withwire 92 which, like 82, is connected with the current supply source.

Stud-cam 8|" is so located relative to blade "88' of a separate startingswitch, the fixed blade of which is blade 81, that starting-switchblades 88-8'| close shortly before running-switch blades: 88-83 areseparated at the end of a cycle as in Fig. 1. Stud-cam 8| is of such alength and so located relative to stud-cam 8| that studcam 8| will notonly have closed blades 88'-8'| before blades 88-83 open at the end of acycle but will cause blades 88'-81 to separate before cam 8| bringsblades 88-83 to again contact being operated by armature H5 and itsholding coi-l I I4. From the foregoing and the figure, it is clear thatthe arrangement is such that a momentary simultaneous pushing of the twobutton switches 89 is effective to start the cycle of operation onlywhile stud-cam 8| forces blade 88' against blade 81, in other words atthe beginning of a cycle to start the same. In any event, the attendantcan tell from running-light 9| whether or not the timer has started uponits cycle of operation.

Motor 48 then operates the timer until cam 8 I rides out from underblade 88' to disconnect The motor then continues to run only if switchblades -96 and 98-99 are closed respectively by stud-cam 94 and bellows|8| which is connected with exhaust line 33 by tubing I82, which closureoccurs in normal operation. If, however, the pressure in exhaust line 33is not sufiiciently high to close contacts 98-99 before blade 88 runsoff of cam 8| (relatively speaking), armature H5 will drop so that motor48 will stop. When the pressure 'in exhaust line 33 subsequently risesenough to cause bellows I 8| to close contacts 98-99, this will notcause motor 48 to run since resistance I I8 in series with coil I II isso high that the pull of coil III on armature I I5 is not sufficient toraise the'same although adequate for holding it once it has been raised.(In other words, this is a permissive system of operating a timer forindividual presses.) After the timer has thus stopped due to the failureof steam under pressure to reach exhaust line 33 at the proper mo--ment, it is necessary for the attendant to manuthe source of troublebefore manually closing the switch. Experience has shown that the cureis ordinarily not sufficiently advanced to spoil the tire at this time.

It is evident that a momentary simultaneous push of the two buttonswitches 89 will sufiice to positively cause motor 48 to continue to runlong enough to drive stud-cam 8| clear of blade 88 thus bringing cam 44to a position where the presses close and, upon such closure, steam issupplied to the tires. Once cam 8| has moved clear of the end of blade88 so that blade 88 contacts blade 83, this contact closes the runningcircuit of motor 48 and in effect disconnects the starting circuit 88,including switches 89, and the permissive circuit, including switchblades 95-98 and 98-99 until the next cycle of operation subsequent tothe manual and simultaneous closing of both switches 89.

As earlier noted briefly, the handle of cock 5| is provided withinsulated spur portion 5| for opening blade 15 from blade 16 of a switchin line 88 in series with the two button starting switches 89, thearrangement being such that in shutting off the air-supply from line 58by cook 51, insulated portion 5| opens the switch so that motor 48 ofthe timer cannot be started as long as the air-supply is shut off.

Upper end I88 of bellows MI is movable, its interior being connected, asearlier mentioned, by pressure pipe I82 with the exhaust line so thatthe presence of any inflating fluid, e. g., steam or hot water, inexhaust line 33 causes bellows end I88 to rise to a positioncorresponding with the then pressure of the exhaust, bellows end I88then closes blades 98-99 to cause motor 48 to start, assuming thatblades 95-96 are then closed by stud-cam 94.

We do not wish to be restricted to air-operatheir valve-operating means.The systems that we have taught would function equally as well 40 with,e. g., electrical operation. Also, with electrical operation we may usea limit switch for the block valve so that the press-reversing valvecannot be opened until after the block valve is in blocking relation tothe supply line and connects;

has been brought to a fluid-supply blocking position. We will not burdenthis specification further by discussing other useful modifications ofthe disclosures herein, such as will be evident to anyone skilled inthis art.

The terms and expressions which we have employed are used as terms ofdescription and not of limitation, and we have no intention, in the useof such terms and expressions, of excluding any equivalents of thefeatures shown and described and portions thereof, but recognize thatvarious modifications are possible within the scope of the inventionclaimed.

We claim:

1. In an apparatus including a press for heatprocessing a hollowarticle, the combination with means for governing the closing andopening of the press, and means for controlling the supply of aninflating fluid under pressure to such hollow article and theexhaustingof such fluid therefrom: of means operatively connected withsaid press-governing means and connected in series with saidfluid-supply controlling means and constructed and arranged topositively block the 75 supply to the interior of the hollow articlebefore said press opening means can act.

2. In an apparatus including a press for heatprocessing a hollowarticle, the combination with means for governing the closing andopening of the press, means for controlling the supply of an inflatingfluid under pressure to such hollow article and the exhausting of suchfluid therefrom: of means operatively connected with said pressgoverningmeans and connected in series with said fluid-supply controlling meansand constructed and arranged to positively block the supply to theinterior of the hollow article and to connect said interior to exhaustbefore such press opening means can act.

3. In an apparatus including a press for heatprocessing a hollowarticle, the combination with a control member, a plurality of pilotmeans operated thereby, a plurality of servomotor means respectivelygoverned by said pilot means, means operatively associated with one ofsaid servomotor means for controlling the opening and closing of. thepress, means operatively associated with one of said servomotor meansfor controlling the supply of an inflating fluid under pressure to suchhollow article and the exhausting of said fluid therefrom, both of saidcontrolling means being operated by its associated said servomotormeans, and piping connecting said fluid controlling means with theinterior of such hollow article: of means operatively connected to andgoverned by the pilot means for the presscontrolling means and connectedin said piping between said fluid-supplying means and said article andarranged to positively block the supply to the interior of the hollowarticle and to connect said interior to exhaust before said pressopeningmeans can act.

4. In a cyclically operated apparatus including a press forheat-processing a hollow article, the combination with a timer, meansfor governing the closing and opening of the press, and means forcontrolling the supplying of an inflating fluid under pressure to suchhollow article and the exhausting of such fluid therefrom, thesequential actuation of said means being governed by said timer: ofmeans operatively connected with the press-governing means and connectedin series with said fluid-supplying means and constructed to positivelyblock the supply to the interior of the hollow article and to connectsaid interior to exhaust before said press-governing means can act.

a. In a cyclically operable apparatus including a press forheat-treating hollow articles, a timer including a time-operated cam, acontrol member positionable by said cam, a plurality of pilot meansoperated by said member, a plurality of servomotor means sequentiallygoverned by said pilot means, means for controlling the operation of thepress, means for controlling the supply of an inflating fluid underpressure to such hollow articles and the exhausting of said fluidtherefrom, each of said controlling means being actuated respectively byan associated one of said servomotor means, and piping connecting saidfluid controlling means with the interior of such hollow articles, meansactuated by one of the servomotor means operatively connected with thepilot means governing said press, said lastnamed means being connectedin said piping between said fluid-supplying means and said article andarranged to positively block the supply to the interior of the hollowarticle and to connect said interior to drain before said pressopeningmeans can act.

6. The combination set forth in claim 3, in which said servomotor meansare pneumaticallyoperated, and the last named means include a delayingmeans having a resistance and a shunting check-valve thereforoperatively connecting the press controlling means and the last namedmeans so that the check-valve is effective only upon a press-openingmovement of the pilot means for governing the opening and closing of thepress.

'7. In a timer system for one or more presses each for vulcanizing ahollow article, the combination of a timer including a cam, an electricmotor for driving said cam at constant speed, and a controlling memberpositioned by said cam; a plurality of means controlled by said membercomprising means for governing the operation of the press, means forsupplying an inflating fluid under pressure to the interior of thehollow article, and means operatively connected in series with the fluidsupplying means and constructed and arranged to block the fluid supplyto the interior of the hollow article and to connect such interior toexhaust before the press operating means can act to cause the opening ofthe press; switch means, including a manually-operable starting portionand a cam-operable portion connected to said motor and adapted to causethe latter to advance said cam to a position beyond a press-closingposition and a predetermined distance beyond a fluid-supplying positionsubsequent to said press closing position; a running switch connected tosaid motor and operated by said cam from a position thereof at apredetermined distance beyond said first named position to that for theend of a cycle, thus leaving a gap in the running of the timer; andmeans including a pressure operated switch having a pressure sensitiveportion connectable to the interior of a hollow article in each pressand a portion connectable by said cam to said motor and operable tocause the continued running of the latter in the gap between the firstnamed and the last named position only if during suchgap each presscontains a hollow article filled with the inflating fluid under at leasta predetermined pressure.

8. The combination set forth in claim 7, in

which the first named means includes a pilot operated by said member andthe means for supplying inflating fluid to the interior of each hollowarticle is servooperated by said pilot, and

including an auxiliary pilot on each press connected in series with saidfirst named pilot and operable to supply such fluid only upon theoperation of said member and the closure of all of said presses, wherebysaid pressure operated switch continues the running of the motor-drivencam through the gap only if each press was closed and contained a hollowarticle filled with the inflating fluid under at least the predeterminedpressure at the first named position of the cam.

9. In a timer system for a press for heatprocessing a hollow article,the combination of a timer including a cam and a pilot actuated thereby,a controlling servooperable member biased toward a safe position andnormally governed by said pilot, an electric motor for driving said camat constant speed relative to said pilot, and a plurality of pilotsactuated by said member, each of said pilots being normally connected toa common source of power; and a plurality of servooperable means eachbiased toward a safe (ill position and normally governable by one of themember-actuated pilots comprising means for governing the operation ofthe press, means for supplying an inflating fluid under pressure to theinterior of the hollow article, and means operatively connected inseries with the fluid supplying meansand constructed and arranged toblock the fluid supply to the interior of the hollow article and toconnect such interior to exhaust before the press operating means canact to cause the opening of the press; whereby, upon the interruption ofthe power supply, the controlling member assumes the stated safeposition and thus prevents the further supply of inflating fluid untilafter the last named means is in its exhausting position and the pressis closed.

10. The combination set forth in claim 9 including switch means, havinga manually operable starting portion and a cam operable portion,connected to said motor and adapted to cause the latter to advance saidcam to a position beyond a press closing position and a predetermineddistance beyond a fluid supplying 1 position subsequent to theattainment of said press closing position; a running switch connected tosaid motor and operated by said'cam from a position thereof at apredetermined distance beyond said first named position to that for theend of a cycle, thus leaving a gap in the running of the timer; andmeans including a pressure operated switch having a pressure sensitiveportion connectable to the interior of a hollow article in each pressand a portion connectable by said cam to said motor and operable tocause the continued running of the latter in the gap between the firstnamed and the last named position only if during such gap each presscontains a hollow article filled with the inflating fluid under. atleast a predetermined pressure.

ROLF A. F. SANDBERG.

PAUL F. K. ERBGUTH.

ED S. SlVHTH, JR.

CERTIFICATE OF CORRECTION.

June 11, 191m.-

Patent No. 2,20h,5'15.

ROLF A. F. SANDBERG, ET AL.

It is hereby certified that error appears in the above numbered patentrequiring correction as follows: Strike out the drawing and insertinstead the following June 11, 1940- v R. A. F. SANDBERG El Au SAFETYCONTRQL FOR VULCANIZER 1 835525 Filed may 26, 1937 T e S G (U 2 U mama.E m W5 U N.

m Ed mm 0 9 V n o c A 1 v F 1 AM REE HOTR'ATER and that the said LettersPatent shouldbe read with this correction therein that the same mayconform to the record of the case in the Patent Office.

Signed and sealed this 6th day of August, A. D, 19140.

Henry Van Arsdale,

Acting Commissioner of .Patents.

(Seal)

